Post Main Sequence Orbital Circularization of Binary Stars in the Large and Small Magellanic Clouds

Abstract

We present results from a study of the orbits of eclipsing binary stars (EBs) in the Magellanic Clouds. The samples comprise 4510 EBs found in the Large Magellanic Cloud (LMC) by the MACHO project, 2474 LMC EBs found by the OGLE-II project (of which 1182 are also in the MACHO sample), 1380 in the Small Magellanic Cloud (SMC) found by the MACHO project, and 1317 SMC EBs found by the OGLE-II project (of which 677 are also in the MACHO sample); we also consider the EROS sample of 79 EBs in the bar of the LMC. Statistics of the phase differences between primary and secondary minima allow us to infer the statistics of orbital eccentricities within these samples. We confirm the well-known absence of eccentric orbit in close binary stars. We also find evidence for rapid circularization in longer period systems when one member evolves beyond the main sequence, as also found by previous studies.

37 pages, 16 figures, accepted for publication in ApJ. Added a new reference and updated information on on line material

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Cited by in corpus (3)

• Artificial Intelligence Approach to the Determination of Physical Properties of Eclipsing Binaries. I. The EBAI Project
• The late type eclipsing binaries in the Large Magellanic Cloud: catalogue of fundamental physical parameters
• Application of the Trend Filtering Algorithm on the MACHO Database